Alzheimer's Disease International (ADI) launched World Alzheimer's Day on September 21, 1994, at the opening of its annual conference in Edinburgh, marking the organization's tenth anniversary. Since 2012, the observance has expanded into World Alzheimer's Month throughout September, with September 21 remaining the campaign's focal date. Dementia, of which Alzheimer's disease is the most common form, affects tens of millions of people worldwide, a number expected to double in the coming decades as populations age. The day raises awareness of early symptoms, encourages early diagnosis, and works to combat the stigma still associated with the disease in many societies. Local and international Alzheimer's associations mark the day and the month with awareness events, medical lectures, and media campaigns, alongside providing psychological support and information for patients, families, and caregivers.